#define _CRT_SECURE_NO_WARNINGS 1

int missingNumber(int* nums, int numsSize) {
    int i = 1;
    int ret = 0;
    for (i = 1; i <= numsSize; i++)
    {
        ret ^= i;
    }
    for (i = 0; i < numsSize; i++)
    {
        ret ^= nums[i];
    }
    return ret;

}